Cavernous Atlantic
Cavernous Atlantic (#1B359B) is a true blue with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (228°, 70%, 36%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary amber. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
An adjectival form of cavern, used principally for the deep darkness of large enclosed spaces. As a color modifier, cavernous implies the slightly cool deep blacks of a Lascaux-style cave or a basilica crypt — darkness with the optical complexity of a space larger than any single light source can fill. Sits in the deep-and-spatial end of the grid.
The body of saltwater between the Americas and Eurasia/Africa — second-largest of Earth's oceans by area, deeper colored by river silt than the Mediterranean. The color refers to the average reflectance of mid-North Atlantic water on a clear day: a saturated, slightly muted blue with the optical depth of cold open water. Deeper than mediterranean, cooler than peacock, with the geographic weight of an ocean named for Atlas at its western horizon.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.